Note: Our very own Michael Brodhead recently wrote a blog post about excon and fog . With his permission, we’re reposting it here. At Engine Yard we make heavy use of fog to interface with back-end cloud providers. Fog in turn uses excon to make HTTP requests. A few features make excon a better choice than Net::HTTP: Better at reusing connections. Automatic retries for idempotent requests. Easy to stub for your unit tests. My coworkers and I at Engine Yard needed to measure the performance of fog’s HTTP calls so we added one more feature to excon: instrumentation. Enter ActiveSupport::Notifications Larry Diehl called my attention to the new-fangled notification API in Rails 3, namely, ActiveSupport::Notifications . Rather than reinvent the wheel, said Larry, it made sense to use an existing API which at least some people would already be familiar with. ActiveSupport::Notif...